The present invention relates to an image predictive coding apparatus and method, image predictive decoding apparatus and method and recording medium. The present invention relates, in particular, to an image predictive coding apparatus and method as well as image predictive decoding apparatus and method for storing digital image data of an image which is a static image or a dynamic image into a recording medium such as an optical disk or for transmitting the data through a communication line. The present invention also relates to a recording medium in which a program including the steps of the image predictive coding method is recorded as well as a recording medium in which a program including the steps of the image predictive decoding method is recorded.
For the purpose of efficiently storing or transmitting a digital image, the image is required to be coded in a compression coding manner. As a method for coding a digital image in a compression coding manner, there is a waveform coding method of sub-band coding, wavelet coding, fractal coding or the like other than discrete cosine transform (referred to as a DCT transform hereinafter) represented by JPEG (Joint Photographic Experts Group) and MPEG (Motion Picture Experts Group). For the purpose of removing a redundant signal between images, an inter-image prediction with a motion compensation is executed, thereby subjecting a differential signal to waveform coding.
According to the MPEG system, an input image is processed while being divided into a plurality of 16xc3x9716 macro blocks. One macro block is further divided into 8xc3x978 blocks and quantized after undergoing 8xc3x978 DCT transform. This is called an intra-frame coding.
On the other hand, according to a motion detection method inclusive of block matching, a prediction macro block having the minimum error with respect to the objective macro block is detected from other frames adjacent in time, the detected prediction macro block is subtracted from the target macroblock thereby forming a differential macro block, and this macro block is quantized after undergoing 8xc3x978 DCT transform. This is called an inter-frame coding, and the prediction macro block is called a prediction signal of the time domain.
A normal image has spatially similar regions, and an image can be approximated to a spatial region by utilizing this characteristic. In a manner similar to that of the prediction signal of the time region, a prediction signal can also be obtained from an identical frame. This is called a spatial prediction signal.
Since spatially adjacent two pixel values are close to each other, the prediction signal of the spatial region is generally located close to the target signal. On the other hand, on the receiving side or the reproducing side, a signal which has been coded and reproduced in the past is required to be used as the prediction signal since the original image is absent. From these two factors, the prediction signal of the spatial region is required to be generated at high speed. This is because the signal used for the generation of a prediction signal has to be decoded and reproduced.
Therefore, the prediction signal of the spatial region is required to be generated in a simple manner, as well as, in high accuracy. Furthermore, a quickly operable construction is required in a coding apparatus and a decoding apparatus.
The coding of image data has been widely used in many international standards such as JPEG, MPEG1, H.261, MPEG2 and H.263. Each of the latter standards has a more improved coding efficiency. That is, much effort has been devoted to further reducing the number of bits than in the conventional standards in expressing the same image quality.
Coding of image data of moving images is comprised of intra-frame coding and prediction frame coding. In a representative hybrid coding system such as MPEG1 Standard, consecutive frames can be classified into the following three different types:
(a) intra-frame (referred to as an xe2x80x9cI-framexe2x80x9d hereinafter);
(b) prediction frame (referred to as a xe2x80x9cP-framexe2x80x9d hereinafter); and
(c) bidirectional prediction frame (referred to as a xe2x80x9cB-framexe2x80x9d hereinafter).
An I-frame is coded independently of the other frames, i.e., the I-frame is compressed without referring to the other frames. A P-frame is coded through motion detection and compensation by using the preceding frame for predicting the contents of a coded frame (it is a P-frame). A B-frame is coded through motion detection and compensation by using information from the preceding frame and information from the subsequent frame for predicting the data of the contents of the B-frame. The preceding frame and the subsequent frames could be an I-frame or a P-frame. The I-frame is coded in intra- modes. The P-frame and the B-frame are coded in intra and prediction mode.
As the characteristics of the coding of the I-frame, P-frame and B-frame are different from one another, the compressing methods thereof differ from one another. The I-frame uses no temporal prediction for the purpose of reducing the redundancy, and therefore, it requires more bits than those of the P-frame and the B-frame.
A description will be herein made taking MPEG2 as an example. It is assumed that the bit rate is 4 Mbits/sec and an image having 30 frames/sec is used. In general, the ratio of the number of bits used for the I- P- and B-frames is 6:3:1. Therefore, the I-frame uses about 420 kbits/s, and the B-frame uses about 70 kbits/s. This is because the B-frame is sufficiently predicted from both directions.
FIG. 14 is a block diagram showing a construction of a prior art image predictive coding apparatus. Since a DCT transform is executed on a block basis, the recent image coding methods are all based on the division of an image into smaller blocks. According to the intra-frame coding, an inputted digital image signal is first of all subjected to a block sampling process 1001 as shown in FIG. 14. Next, the blocks obtained after the block sampling process 1001 are subjected to a DCT transform process 1004 and thereafter subjected to a quantizing process 1005 and a run length Huffman variable length coding (VLC: Variable Length Coding; entropy coding) process 1006. On the other hand, according to the prediction frame coding, an inputted digital image is subjected to a motion compensating process 1003, and the motion-compensated block (i.e., the predicted block) is subjected to the DCT transform process 1004. Next, the quantizing process 1005 and the run length Huffman VLC coding (entropy coding) process 1006 are executed.
The fact that the block-based DCT transform process 1004 removes or reduces a spatial redundancy inside the target block to be processed and the fact that the motion detecting and compensating processes 1002 and 1003 remove or reduce a temporal redundancy between adjacent frames are known from the conventional image coding techniques. Further, the run length Huffman VLC coding or other entropy coding processes 1006 executed after the DCT transform process 1004 and the quantizing process 1005 removes statistical redundancy between quantized DCT transform coefficients. However, the process is executed only on the blocks within an image.
A digital image has a spatially great redundancy as an inherent characteristic. This redundancy exists not only in the blocks inside a frame but also between blocks over blocks. However, the fact that no actual method uses a process for removing the redundancy between blocks of an image is apparent from the above description.
According to the existing image coding method, the DCT transform process 1004 or another transform process is executed on the block basis due to restrictive conditions in terms of hardware formation and calculation.
Although the spatial redundancy is reduced through the block-based transform process, it is restricted to the inside of one block. The redundancy between adjacent two blocks is not satisfactorily considered. The redundancy, however, can be further reduced when the intra-frame coding which consistently consumes a great number of bits.
Furthermore, the fact that the block-based DCT transform process removes or reduces the spatial redundancy inside the target block to be processed and the fact that the motion predicting and compensating processes remove or reduce the temporal redundancy between adjacent two frames are known from the existing image coding techniques. A zigzag scan and the run length Huffman VLC coding or another entropy coding process, which are executed after the DCT transform process and the quantizing process, remove the statistical redundancy in quantized DCT transform coefficients, however, they are still restricted to the inside of one block.
A digital image inherently includes a great spatial redundancy. This redundancy exists not only inside a block but also between blocks over blocks of an image. There is no existing method uses the process for removing the redundancy between blocks of one image at all except for the DC coefficient prediction of JPEG, MPEG1 and MPEG2.
According to MPEG1 and MPEG2, the DC coefficient prediction is executed by subtracting the DC value of the preceding coded block from the currently coded block. This is a simple predicting method which does not have an adaptiveness or mode switching when the prediction is inappropriate. Further, it merely includes DC coefficients.
According to the current state of the concerned technical field, the zigzag scan is used for all blocks prior to the run length coding. No attempt at making scan adaptive on the basis of the data of the contents of the block has been made.
FIG. 22 is a block diagram showing a construction of a prior art image predictive coding apparatus. In FIG. 22, the prior art image predictive coding apparatus is provided with a block sampling unit 2001, a DCT transform unit 2003, a quantizing unit 2004, a zigzag scan unit 2005 and an entropy coding unit 2006. In this specification, the term xe2x80x9cunitxe2x80x9d device a circuit device. According to the intra-frame coding (i.e., coding inside a frame), an inputted image signal is subjected to a block sampling process 2001 and thereafter subjected directly to a DCT transform process 2003. Then, a quantizing process 2004, a zigzag scan process 2005 and an entropy coding process 2006 are sequentially executed. On the other hand, according to the inter-frame coding (i.e., coding between frames, i.e., prediction frame coding), a motion detecting and compensating process is executed in a unit 2011 after the block sampling process 2001, and then a prediction error is obtained from an adder 2002 by subtracting a detection value obtained from the unit 2011 from the image data obtained from the block sampling 2001. Further, this prediction error is subjected to the DCT transform process 2003 and then to the quantizing process 2004, zigzag scan process 2005 and entropy coding process 2006 similar to the intra-frame coding.
In a local decoder provided in the image predictive coding apparatus shown in FIG. 22, an inverse quantizing process and an inverse DCT transform process are executed in units 2007 and 2008. According to the inter/frame coding, a prediction value obtained through motion detection and compensation is added by an adder 2009 to the prediction error reconstructed by the units 2007 and 2008, and the addition value device locally decoded image data. The decoded image data is stored into a frame memory 2010 of the local decoder. Finally, a bit stream is outputted from the entropy coding unit 2010 and transmitted to the image predictive decoding apparatus of the other party.
FIG. 23 is a block diagram showing a construction of a prior art image predictive decoding apparatus. The bit stream is decoded by a variable length decoder (VLD: Variable Length Decoding) unit (or an entropy decoding unit) 2021, and the decoded image data is then subjected to an inverse quantizing process and an inverse DCT transform process in units 2023 and 2024. According to the inter-frame coding, a prediction value which is obtained through motion detection and compensation and formed by a unit 2027 is added by an adder 2025 to the prediction error reconstructed, thereby forming locally decoded image data. The locally decoded image data is stored into a frame memory 1026 of the local decoder.
According to the existing image coding techniques, the DCT transform process or other transform process is executed on the block basis due to the restrictive conditions in terms of hardware formation and calculation. The spatial redundancy will be reduced through the block-based transform. However, it is restricted to the inside of a block. The redundancy between adjacent blocks is not satisfactorily considered. In particular, the intra-frame coding which consistently consumes a great amount of bits is not satisfactorily considered.
A first object of the present invention is to provide an image predictive coding apparatus and method as well as image predictive decoding apparatus and method capable of simply generating prediction image data of the spatial region at high speed with high accuracy.
A second object of the present invention is to provide an image predictive coding apparatus and method as well as image predictive decoding apparatus and method capable of removing the redundancy in a block further than in the prior art image predictive coding apparatus and image predictive decoding apparatus and more efficiently coding or decoding image data.
Further, a third object of the present invention is to provide an image predictive coding, apparatus and method as well as image predictive decoding apparatus and method capable of improving the efficiency of an entropy coding process by solving the problem that important transform coefficients are concentrated on different regions of a block depending on the internal properties of image data and by determining the correct scan method for the block.
Furthermore, a fourth object of the present invention is to provide a recording medium in which the steps of the image predictive coding method or the image predictive decoding method are recorded.
According to the first aspect of the present invention, there is provided an image predictive coding apparatus comprising:
dividing device operable to divide inputted image data to be coded into image data of a plurality of small regions which are adjacent to one another;
first generating device operable, when code the image data of a target small region to be processed among the image data of the plurality of small regions which are divided by the dividing device and adjacent to one another, to use image data of a reconstructed small region adjacent to the image data of the target small region to be processed as image data of an intra-frame prediction small region of the target small region to be processed, to use the image data of the intra-frame prediction small region as image data of an optimum prediction small region and to generate image data of a difference small region which are differences between the image data of the objective small region to be processed and the image data of the optimum prediction small region;
coding device operable to code the image data of the difference small region generated by the generating device;
decoding device operable to decode the image data of the difference small region coded by the coding device; and
second generating device operable to generate image data of a reproduced reproduction small region by adding the image data of the difference small region decoded by the decoding device to the image data of the optimum prediction small region.
Also, according to the second aspect of the present invention, there is provided an image predictive coding apparatus comprising:
dividing device operable to divide inputted image data to be coded into image data of a plurality of small regions which are adjacent to one another;
first generating device operable, when coding an objective small region to be processed among a plurality of small regions which are divided by the dividing device and adjacent to one another, to use only significant image data indicated by an inputted significance signal representing whether or not the coded image data is significant as image data of an intra-frame prediction small region of the objective small region to be processed among image data of a reproduced reproduction small region adjacent to the image data of the objective small region to be processed, to use the image data of the intra-frame prediction small region as image data of an optimum prediction small region and to generate image data of a difference small region which are differences between the image data of the objective small region to be processed and the image data of the optimum prediction small region;
coding device operable to code the image data of the difference small region generated by the first generating device;
decoding device operable to decode the image data of the difference small region coded by the coding device; and
second generating device operable to generate image data of a reproduced reproduction small region by adding the image data of the difference small region decoded by the decoding device to the image data of the optimum prediction small region.
Further, according to the third aspect of the present invention, there is provided an image predictive decoding apparatus comprising:
analyzing device operable to analyze an inputted coded image data series and outputting an image difference signal;
decoding device operable to decode image data of a reproduction difference small region from the image difference signal outputted from the analyzing device;
a line memory for storing therein image data for generating image data of a predetermined intra-frame prediction small region;
generating device operable to execute a prediction signal generating process on the image data from the line memory to thereby use reconstructed image data adjacent to the image data of the reproduction difference small region as image data of an intra-frame prediction small region and outputting the image data of the intra-frame prediction small region as image data of an optimum prediction small region; and
adding device operable to add the image data of the reproduction difference small region from the decoding device to the image data of the optimum prediction small region from the generating device, outputting image data for generating image data of an intra-frame prediction small region of the result of addition and storing the data into the line memory.
Still further, according to the fourth aspect of the present invention, there is provided an image predictive decoding apparatus comprising:
analyzing device operable to analyze an inputted coded image data series and outputting an image difference signal, a motion vector signal and a control signal;
decoding device operable to decode the image difference signal outputted from the analyzing device into image data of a reproduction difference small region;
control device operable to output a switching signal for controlling motion compensating device and generating device to selectively operate based on the control signal outputted from the analyzing device;
a frame memory for storing therein predetermined reproduction image data;
a line memory for storing therein image data for generating image data of a predetermined intra-frame prediction small region;
motion compensating device operable to execute a motion compensating process on an inputted motion vector signal in response to the switching signal from the control device to thereby generate image data of a time prediction small region from the frame memory and outputting the data as image data of an optimum prediction small region;
generating device operable to execute a prediction signal generating process on the image data from the line memory in response to the switching signal from the control device to thereby use reconstructed image data adjacent to the image data of the reproduction difference small region as image data of an intra-frame prediction small region and outputting the image data of the intra-frame prediction small region as image data of an optimum prediction small region; and
adding device operable to add the image data of the reproduction difference small region from the decoding device to the image data of the optimum prediction small region from the generating device to thereby output reproduction image data of the result of addition, storing the reproduction image data into the frame memory and storing only the image data for generating the image data of the intra-frame prediction small region into the line memory.
Also, according to the fifth aspect of the present invention, there is provided an image predictive decoding apparatus comprising:
analyzing device operable to analyze an inputted coded image data series and outputting a compressed shape signal and an image difference signal;
first decoding device operable to decode the compressed shape signal outputted from the analyzing device into a reproduction shape signal;
second decoding device operable to decode the image difference signal outputted from the analyzing device into image data of a reproduction difference small region;
a line memory for storing therein image data for generating image data of a predetermined intra-frame prediction small region;
generating device operable to execute a prediction signal process on the image data from the line memory to thereby use only significant image data expressed by the reproduction shape signal as image data of an intra-frame prediction small region among the reconstructed image data adjacent to the image data of the reproduction difference small region and outputting the image data of the intra-frame prediction small region as image data of an optimum prediction small region; and
adding device operable to add the image data of the reproduction difference small region from the second decoding device to the image data of the optimum prediction small region from the generating device to thereby output image data of the result of addition and storing only image data for generating the image data of the intra-frame prediction small region into said line memory.
Further, according to the sixth aspect of the present invention, there is provided an image predictive decoding apparatus comprising:
analyzing device operable to analyze an inputted coded image data series and outputting a compressed shape signal, an image difference signal, a motion vector signal and a control signal;
first decoding device operable to decode the compressed shape signal outputted from the analyzing device into a reproduction shape signal;
second decoding device operable to decode the image difference signal outputted from the analyzing device into image data of a reproduction difference small region;
control device operable to output a switching signal for controlling the motion compensating device and generating device to selectively operate based on the control signal outputted from the analyzing device;
a frame memory for storing therein predetermined reproduction image data;
a line memory for storing therein image data for generating image data of a predetermined intra-frame prediction small region;
motion compensating device operable to execute a motion compensating process on the reproduction image data from the frame memory based on the motion vector signal outputted from the analyzing device in response to the switching signal outputted from the control device to thereby generate image data of a time prediction small region and outputting the data as image data of an optimum prediction small region;
generating device operable to execute a prediction signal process on the image data from the line memory in response to the switching signal outputted from the control device to hereby use only significant image data expressed by the reproduction shape signal among the reconstructed image data adjacent to the image data of the reproduction difference small region as the image data of the intra-frame prediction small region and outputting the image data of the intra-frame prediction small region as image data of an optimum prediction small region; and
adding device operable to add the image data of the reproduction difference small region from the second decoding device to the image data of the optimum prediction small region from the generating device to thereby output reproduction image data of the result of addition, storing the reproduction image data into the frame memory and storing only image data for generating the image data of the intra-frame prediction small region into the line memory.
According to the seventh aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
transforming device operable to transform the image data of the blocks sampled by the sampling device into coefficient data of a predetermined transform domain;
a block memory for storing therein coefficient data of a restored block,
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of a block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmitting an identifier indicating the selected prediction block in an indication bit form to an image predictive decoding apparatus;
first adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of a prediction error of the result of subtraction;
quantizing device operable to quantize the coefficient data of the prediction error outputted from the first adding device;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error from the quantizing device and transmit the coded coefficient data of the prediction error to the image predictive decoding apparatus;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error from the quantizing device and output the coefficient data of the restored block;
second adding device operable to add the coefficient data of the prediction block outputted from the determining device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby output coefficient data of the restored block and storing the data into the block memory; and
inverse transforming device operable to inverse transform the coefficient data of the block outputted from the second adding device, thereby generating image data of the restored block.
Also, according to the eighth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
transforming device operable to transform the image data of the plurality of blocks sampled by the sampling device into coefficient data of a predetermined transform domain;
quantizing device operable to quantize the coefficient data of the transform domain from the transforming device;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of a block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmit an identifier indicating the selected prediction block in an indication bit form to an image predictive decoding apparatus;
first adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of a prediction error of the result of subtraction;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error from the first adding device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
second adding device operable to add the coefficient data of the prediction error from the first adding device to the coefficient data of the prediction block outputted from the determining device to thereby restore and output the quantized coefficient data of the current block and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the current block outputted from the second adding device and outputting the resulting data; and
inverse transforming device operable to inverse transform the coefficient data of the current block from the inverse quantizing device, thereby generating image data of the restored block.
Further, according to the ninth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
compensating device operable to execute a motion compensating process on the image data of an inputted block, thereby generating and outputting image data of a prediction error of a motion-compensated block;
first adding device operable to subtract the image data of the prediction error of the block outputted from the compensating device from the image data of the block outputted from the sampling device, thereby outputting image data of the block of the result of subtraction;
transforming device operable to transform the image data of the block outputted from the first adding device into coefficient data of a predetermined transform domain;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of the block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmitting an identifier indicating the selected prediction block in an indication bit form to an image predictive decoding apparatus;
second adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of the prediction error of the result of subtraction;
quantizing device operable to quantize the coefficient data of the prediction error outputted from the second adding device;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error from the quantizing device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error from the quantizing device and output the coefficient data of the restored block;
third adding device operable to add the coefficient data of the prediction block outputted from the determining device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby output the coefficient data of the restored block and storing the data into the block memory;
inverse transforming device operable to inverse transform the coefficient data of the block outputted from the third adding device, thereby generating image data of the restored block; and
fourth adding device operable to add the image data of the prediction error of the motion-compensated block outputted from the motion compensating device to the image data of the restored block from the inverse transforming device, thereby outputting the image data of the restored block to the compensating device.
Still further, according to the tenth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
compensating device operable to execute a motion compensating process on the image data of an inputted block, thereby generating and outputting image data of a prediction error of a motion-compensated block; block; and
fourth adding device operable to add the image data of the prediction error of the motion-compensated block outputted from the motion compensating device to the image data of the restored block from the inverse transforming device, thereby outputting the image data of the restored block to the compensating device.
According to the eleventh aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the seventh aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by said extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from the decoding device and outputting the resulting data;
third adding device operable to add the coefficient data of the prediction block outputted from the further predicting device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory; and
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the third adding device and outputting the image data of the restored current block.
Also, according to the twelfth aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus
first adding device operable to subtract the image data of the prediction error of the block outputted from the compensating device from the image data of the block outputted from the sampling device, thereby outputting image data of the block of the result of subtraction;
transforming device operable to transform the image data of the block outputted from the first adding device into coefficient data of a predetermined transform domain;
quantizing device operable to quantize the coefficient data of the transform domain from said transforming device;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of the block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmitting an identifier indicating the selected prediction block in an indication bit form to an image predictive decoding apparatus;
second adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of the prediction error of the result of subtraction;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error from the second adding device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
third adding device operable to add the coefficient data of the prediction error from the second adding device to the coefficient data of the prediction block outputted from the determining device to thereby restore and output the coefficient data of the quantized current block and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the current block outputted from the third adding device and output the resulting data;
inverse transforming device operable to inverse transform the coefficient data of the current block from the inverse quantizing device, thereby generating image data of the restored of the eighth aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block,
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
third adding device operable to add the coefficient data of the prediction block outputted from the predicting device to the coefficient data of the prediction error outputted from the decoding device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into said block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from the third adding device and outputting the resulting data; and
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the inverse quantizing device and output the image data of the restored current block.
Further, according to the thirteenth aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the ninth aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from said decoding device and output the resulting data;
third adding device operable to add the coefficient data of the prediction block outputted from the further predicting device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory;
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the third adding device and output the image data of the restored current block;
further compensating device operable to execute a motion compensating process on the image data of the current block outputted from the further inverse transforming device, thereby outputting motion-compensated prediction error data; and
fifth adding device operable to subtract the motion-compensated prediction error data outputted from the further compensating device from the image data of the current block outputted from the further inverse transforming device, thereby outputting the image data of the restored block of the result of subtraction.
Still further, according to the fourteenth aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the tenth aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
third adding device operable to add the coefficient data of the prediction block outputted from the predicting device to the coefficient data of the prediction error outputted from the decoding device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from the third adding device and output the resulting data;
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the inverse quantizing device and output the image data of the restored current block;
further compensating device operable to execute a motion compensating process on the image data of the current block outputted from the further inverse transforming device, thereby outputting motion-compensated prediction error data; and
fifth adding device operable to subtract the motion-compensated prediction error data outputted from the further compensating device from the image data of the current block outputted from the further inverse transforming device, thereby outputting the image data of the restored block of the result of subtraction.
According to the fifteenth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
transforming device operable to transform the image data of the blocks sampled by the sampling device into coefficient data of a predetermined transform domain;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of a block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data and scan method of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmitting an identifier indicating the selected prediction block and scan method in an indication bit form to an image predictive decoding apparatus;
first adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of a prediction error of the result of subtraction;
quantizing device operable to quantize the coefficient data of the prediction error outputted from the first adding device;
scanning device operable to execute a scan process on the coefficient data of the prediction error from the quantizing device according to the scan method determined by the determining device and outputting the coefficient data of the prediction error obtained after the scan process;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error obtained after the scan process outputted from the scanning device and transmit the coded coefficient data of the prediction error to the image predictive decoding apparatus;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error from the quantizing device and output the coefficient data of the restored block;
second adding device operable to add the coefficient data of the prediction block outputted from the determining device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby output coefficient data of the restored block and storing the data into the block memory; and
inverse transforming device operable to inverse transform the coefficient data of the block outputted from the second adding device, thereby generating image data of the restored block.
Also, according to the sixteenth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
transforming device operable to transform the image data of the plurality of blocks sampled by the sampling device into coefficient data of a predetermined transform domain;
quantizing device operable to quantize the coefficient data of the transform domain from the transforming device;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of a block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data and scan method of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmit an identifier indicating said selected prediction block and scan method in an indication bit form to an image predictive decoding apparatus;
first adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of a prediction error of the result of subtraction;
scanning device operable to execute a scan process on the coefficient data of the prediction error from the first adding device according to the scan method determined by the determining device and outputting the coefficient data of the prediction error obtained after the scan process;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error obtained after the scan process outputted from the scanning device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
second adding device operable to add the coefficient data of the prediction error from the first adding device to the coefficient data of the prediction block outputted from the determining device to thereby restore and output the quantized coefficient data of the current block and storing the data into said block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the current block outputted from the second adding device and output the resulting data; and
inverse transforming device operable to inverse transform the coefficient data of the current block from the inverse quantizing device, thereby generating image data of the restored block.
Further, according to the seventeenth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
compensating device operable to execute a motion compensating process on the image data of an inputted block, thereby generating and outputting image data of a prediction error of a motion-compensated block;
first adding device operable to subtract the image data of the prediction error of the block outputted from the compensating device from the image data of the block outputted from the sampling device, thereby outputting image data of the block of the result of subtraction;
transforming device operable to transform the image data of the block outputted from the first adding device into coefficient data of a predetermined transform domain;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of the block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data and scan method of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmit an identifier indicating the selected prediction block and scan method in an indication bit form to an image predictive decoding apparatus;
second adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby outputting coefficient data of the prediction error of the result of subtraction;
quantizing device operable to quantize the coefficient data of the prediction error outputted from the second adding device;
scanning device operable to execute a scan process on the coefficient data of the prediction error from the quantizing device according to the scan method determined by the determining device and outputting the coefficient data of the prediction error obtained after the scan process;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error obtained after the scan process outputted from the scanning device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error from the quantizing device and outputting the coefficient data of the restored block;
third adding device operable to add the coefficient data of the prediction block outputted from the determining device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby output the coefficient data of the restored block and storing the data into the block memory;
inverse transforming device operable to inverse transform the coefficient data of the block outputted from the third adding device, thereby generating image data of the restored block; and
fourth adding device operable to add the image data of the prediction error of the motion-compensated block outputted from the motion compensating device to the image data of the restored block from the inverse transforming device, thereby outputting the image data of the restored block to the compensating device.
Still further, according to the eighteenth aspect of the present invention, there is provided an image predictive coding apparatus comprising:
sampling device operable to sample an inputted image signal into image data of a plurality of blocks each including pixel values of a two-dimensional array;
compensating device operable to execute a motion compensating process on the image data of an inputted block, thereby generating and outputting image data of a prediction error of a motion-compensated block;
first adding device operable to subtract the image data of the prediction error of the block outputted from the compensating device from the image data of the block outputted from the sampling device, thereby outputting image data of the block of the result of subtraction;
transforming device operable to transform the image data of the block outputted from the first adding device into coefficient data of a predetermined transform domain;
quantizing device operable to quantize the coefficient data of the transform domain from the transforming device;
a block memory for storing therein coefficient data of a restored block;
predicting device operable to form coefficient data of a plurality of prediction blocks for the coefficient data of the block transformed by the transforming device based on the coefficient data of the block which has been previously reconstructed and stored in the block memory;
determining device operable to determine, select and output the coefficient data and scan method of a most efficient prediction block among the coefficient data of the plurality of prediction blocks formed by the predicting device and transmit an identifier indicating said selected prediction block and scan method in an indication bit form to an image predictive decoding apparatus;
second adding device operable to subtract the coefficient data of the prediction block selected by the determining device from the coefficient data of the current block at the present timing, thereby output coefficient data of the prediction error of the result of subtraction;
scanning device operable to execute a scan process on the coefficient data of the prediction error from the second adding device according to the scan method determined by the determining device and output the coefficient data of the prediction error obtained after the scan process;
coding device operable to code in an entropy coding manner the coefficient data of the prediction error obtained after the scan process outputted from the scanning device and transmitting the coded coefficient data of the prediction error to the image predictive decoding apparatus;
third adding device operable to add the coefficient data of the prediction error from the second adding device to the coefficient data of the prediction block outputted from the determining device to thereby restore and output the coefficient data of the quantized current block and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the current block outputted from the third adding device and output the resulting data;
inverse transforming device operable to inverse transform the coefficient data of the current block from the inverse quantizing device, thereby generating image data of the restored block; and
fourth adding device operable to add the image data of the prediction error of the motion-compensated block outputted from the motion compensating device to the image data of the restored block from the inverse transforming device, thereby outputting the image data of the restored block to the compensating device.
According to the nineteenth aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the fifteenth aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse scanning device operable to execute an inverse scan process on the coefficient data of the prediction error outputted from the decoding device based on the scan method indicated by the indication bit extracted by the extracting device and outputting the coefficient data of the prediction error obtained after the inverse scan process;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error obtained after the inverse scan process outputted from the scanning device and outputting the resulting data;
third adding device operable to add the coefficient data of the prediction block outputted from the further predicting device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory; and
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the third adding device and outputting the image data of the restored current block.
Also, according to the twentieth aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the sixteenth aspect of the present invention, comprising:
extracting device operable to extract the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse scanning device operable to execute an inverse scan process on the coefficient data of the prediction error outputted from the decoding device based on the scan method indicated by the indication bit extracted by the extracting device and output the coefficient data of the prediction error obtained after the inverse scan process;
third adding device operable to add the coefficient data of the prediction block outputted from the predicting device to the coefficient data of the prediction error outputted from the inverse scanning device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from the third adding device and output the resulting data; and
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the inverse quantizing device and output the image data of the restored current block.
Further, according to the twenty-first aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the seventeenth aspect of the present invention, comprising:
extracting device operable to extracte the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse scanning device operable to execute an inverse scan process on the coefficient data of the prediction error outputted from the decoding device based on the scan method indicated by the indication bit extracted by the extracting device and outputting the coefficient data of the prediction error obtained after the inverse scan process;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error obtained after the inverse scan process outputted from the inverse scanning device and output the resulting data;
third adding device operable to add the coefficient data of the prediction block outputted from the further predicting device to the coefficient data of the prediction error outputted from the inverse quantizing device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory;
further inverse transforming device operable to inverse transform the coefficient data of the current block outputted from the third adding device and output the image data of the restored current block;
further compensating device operable to execute a motion compensating process on the image data of the current block outputted from the further inverse transforming device, thereby outputting motion-compensated prediction error data; and
fifth adding device operable to subtract the motion-compensated prediction error data outputted from the further compensating device from the image data of the current block outputted from the further inverse transforming device, thereby outputting the image data of the restored block of the result of subtraction.
Still further, according to the twenty-second aspect of the present invention, there is provided an image predictive decoding apparatus provided in correspondence with the image predictive coding apparatus of the eighteenth aspect of the present invention, comprising:
extracting device operable to extracte the indication bit from received data received from the image predictive coding apparatus;
a block memory for storing therein coefficient data of the restored block;
further predicting device operable to generate and output coefficient data of a prediction block for the coefficient data of the current block at the present timing included in the received data by device of the coefficient data of the block which has been previously restored and stored in the block memory based on the prediction block indicated by the indication bit extracted by the extracting device;
decoding device operable to decode the received data in an entropy decoding manner and outputting the decoded coefficient data of the prediction error;
inverse scanning device operable to execute an inverse scan process on the coefficient data of the prediction error outputted from the decoding device based on the scan method indicated by the indication bit extracted by the extracting device and output the coefficient data of the prediction error obtained after the inverse scan process;
third adding device operable to add the coefficient data of the prediction block outputted from the predicting device to the coefficient data of the prediction error outputted from the inverse scanning device to thereby restore and output the coefficient data of the current block at the present timing and storing the data into the block memory;
inverse quantizing device operable to inverse quantize the coefficient data of the prediction error outputted from the third adding device and output the resulting data;
further inverse transforming device operable to inverse transforming the coefficient data of the current block outputted from the inverse quantize device and output the image data of the restored current block;
further compensating device operable to execute a motion compensating process on the image data of the current block outputted from the further inverse transforming device, thereby outputting motion-compensated prediction error data; and
fifth adding device operable to subtract the motion-compensated prediction error data outputted from the further compensating device from the image data of the current block outputted from the further inverse transforming device, thereby outputting the image data of the restored block of the result of subtraction.
Also, according to the twenty-third aspect of the present invention, there is provided an image predictive coding method including steps obtained by replacing the device of the above-mentioned image predictive coding apparatus.
Further, according to the twenty-fourth aspect of the present invention, there is provided an image predictive decoding method including steps obtained by replacing the device of the above-mentioned image predictive decoding apparatus.
Also, according to the twenty-fifth aspect of the present invention, there is provided a recording medium in which a program including the steps of the above-mentioned image predictive coding method.
Further, according to the twenty-sixth aspect of the present invention, there is provided a recording medium in which a program including the steps of the above-mentioned image predictive decoding method.